The question is published on by Tutorial Guruji team.
window.opener.location.href = window.opener.location.href;
The opener tab gets focused in Firefox and this is undesirable. I don’t get this behavior in Chrome. It may be due to a Firefox update because this is an old system and this problem is not reported previously.
This is https://bugzilla.mozilla.org/show_bug.cgi?id=1694927 which is fixed in Firefox 87.